This invention relates to a chair cushion and method for producing a chair cushion. It relates particularly to the manufacture of chair cushions used for one and two piece office chairs having upholstered chair seats and backs. A one piece office chair has a padded and upholstered chair seat and a padded and upholstered chair back combined as a single integral unit, usually enclosed in a molded rigid one piece plastic outer shell. A two piece office chair has the upholstered and padded chair seat and a separate, but connected, padded and upholstered chair back which are usually enclosed in two separate, but connected, molded rigid plastic outer shells.
In recent years, most chair cushions used for office type chair seats and backs were made of a soft, resilient plastic foam material, such as a polyurethane foam, that was either cut from a sheet of the foam material or custom molded to the desired shape and size. The polyurethane foam cushion was then covered with upholstery material and attached to the molded rigid plastic outer shell as part of the chair assembly.
In the past, the foam chair cushions were made of a single piece of foam material, either cut from a sheet or custom molded to the desired shape and size in a mold. The foam material used in these prior chair cushions was of a uniform density and provided a uniform soft resiliency over the entire surface of the cushion. In order to provide sufficient comfort in the seat portion, the cushions were often quite thick which often detracted from the appearance of the chair and made upholstering the cushion more difficult. While such chair cushions were simple to produce they did not always provide good comfort to the user and often would lose much of their resiliency over a period of time.